Vesicular Stomatitis Virus (VSV) is a lipid-enveloped, RNA-containing virus which is rapidly cytocidal in an extremely wide range of animal cells in tissue culture. The VSV G protein is the only major glycoprotein species synthesized in VSV-infected cells, and complex, serum glycoprotein-like oligosaccharides are added to the G polypeptide by host glycosyl transferases. VSV acquires its lipid-envelope and membrane glycoprotein by "budding off" from modified cellular membranes. VSV infected cells in tissue culture will be used in the proposed research as a prototypic model system for examining: (1) the molecular and subcellular mechanisms of glycosylation and maturation of cell and virus membrane glycoprotein; and (2) the specificity of glycosylation of cellular and virus glycoproteins. The avian RNA tumor viruses, which include both the leukosis and sarcoma viruses, are also lipid-enveloped, RNA-containing viruses, but they are non-cytocidal and have a narrow and specific host range. This group of viruses can be divided into different subgroups on the basis of their membrane glycoprotein, which is the specific determinant of the host range along with specific "receptors" on the host cell plasma membranes. The possible role of the carbohydrate moieties in the specific functions of the viral membrane glycoprotein will be examined by comparative analysis of the oligosaccharide side chains of glycoproteins from the different subgroups of the avian RNA tumor viruses.